the autoleveling was turned on. I'm not sure why the worms happened, its not oozing of material but failed adhesion i think. I didn't change any setting in cura and even updated it to 2.5 with same results.
Because of the problems i had with the printer i returned it. i am very disappointed with how it performed. with a 3500 euro machine you expect performance and reliability - unfortunately the UL3 didn't live to those expectation very disappointing.